1. Field of the Invention
The embodiments discussed herein are related to a semiconductor device.
2. Background of the Related Art
A semiconductor device includes a power semiconductor element and is used as a power converting device or a switching device. As one example, it is possible to configure a semiconductor device that functions as a switching device by connecting semiconductor elements, including IGBT (Insulated Gate Bipolar Transistors), MOSFET (Metal Oxide Semiconductor Field Effect Transistors), and the like.
A semiconductor device includes a main circuit board, which has a main circuit wiring pattern formed on a front surface and a metal plate formed on a rear surface and which is equipped with an insulating layer, and one or more semiconductor elements mounted via solder on the main circuit wiring pattern (see, for example, Japanese Laid-open Patent Publication No. 2013-258321). Heat generated by the semiconductor elements dissipates from the metal plate.
In this semiconductor device, to ensure that the main circuit wiring pattern sufficiently transfers away the heat generated by the semiconductor elements, it is desirable to make pattern thicker so as to increase the capacity, i.e., the amount of heat that can be transferred.
However, when the thickness of the main circuit wiring pattern is increased in this type of semiconductor device, it is necessary, both for the etching process that forms the main circuit wiring pattern and the provision of clearances, to provide a certain width between traces in the main circuit wiring pattern. This leads to an increase in the size of the semiconductor device.
When, as one example, the thickness of the main circuit wiring pattern is limited to avoid an increase in the size of the semiconductor device, as described above the heat capacity, i.e., the amount of heat generated by the semiconductor elements that can be transferred by the main circuit wiring pattern also becomes limited. This means that this semiconductor device has a problem in that when the semiconductor elements are operated, the temperature quickly rises and exceeds the range of operating temperatures, resulting in the risk of breakdown and malfunctioning.